Fiber breaks and/or degradation in a fiber feeding a distributed antenna system (DAS) network can have a large impact on a system's availability. Network operators typically look for a high-degree of network availability (for example, “0.9999” or higher). A network availability of 0.9999 requires a network be unavailable for no more than 1 hour per year, whereas a network availability of 0.99999 requires a network be unavailable for no more than 1 hour every ten years. One fiber break that causes a DAS network to be unavailable for 10 hours while the fiber break is isolated and repaired would lower availability to 0.999. Oftentimes fiber breaks take even longer to isolate and repair.
Adverse changes to a fiber-based network can happen in many different ways. Examples include digging near fiber optic cabling that causes damage to fiber, damaging the cable by a maintenance worker stepping on, bending, or breaking a fiber. Aerial-mounted fiber can be damaged during accidents involving the poles hanging the fiber. Optical connectors can become degraded by damage and/or dirt. These are just a few of the fiber degradation scenarios, any of which can cause degraded or loss of service on that fiber for extended periods of time. Due to the time required to isolate and repair fibers, redundant paths are often used in order to keep the system up as much as possible. Since fiber damage tends to be a local event, redundant fibers are usually run via completely different paths. In this way, any local damage done to the fiber does not affect the redundant path. In one application of a DAS network that makes use of redundant fibers, both a hub and remote node connected by the redundant fibers includes active switching devices in order to switch from a primary fiber to a secondary fiber in the event of a break (or other degradation of the primary fiber). However, remote nodes are often located in isolated areas with limited power resources and space for accommodating optical switching equipment.